I'm pretty new to this, so forgive me if I get some things wrong. I am working with a piece of equipment that uses an Arduino Pro Mini. When I first got to it, I realized that some of the code was incorrect and wanted to fix it. Unfortunately, my Pro Mini is soldered into the board with the labels and pins down, so the only accessible pins are the top six, and even those aren't labeled. The reset button is also upside down. I tried using a FT232H FTDI hooked up (using a pinout because of the aforementioned no labels)
D0-> TX
D1-> RX
which I was told should work, but when I plug in the micro-usb into the FT232H and try to upload the sketch, it gives me the error
avrdude: stk500_getsync(): not in sync: resp=0x00
and also blinks green but has a constant red light (from what I can see from looking under the board). Because this Pro Mini controls my equipment, I'm wary of doing anything too intense. Any ideas of how to fix this without breaking my apparatus?
Update! I changed the pinning, and the IDE told me that it uploaded, but it still won't run the program! Help!